Self-retaining medullary extension splint



S. JONAS ET AL SELF-RETAINING MEDULLAY EXTENSION SPLINT March 23, 1954 Filed Dec. 30, 1952 INVENTOR ATTORNEY Patented Mar. 23, 1954 SELF-RETAIN ING MEDUL-LARY EXTENSION SPLINT Salo Jonas and Albert M. Jonas, New Haven, Conn.

- Application December 3o, 1952, serial No. 328,562

9 Claims. (Cl. 12S-92) This invention relates `to a self-retaining medullary extension pin vand more particularly to ak self-retaining pin or splint adapted for use ,in connection with the treatment of fractured bones and particularly the longer bones of the skeleton.

kIt has been the custom in reduction of fractures to introduce a pin into the medullary cavity or channel of the bone after the bone fragments have been aligned and the fracture reduced sov that therpin will holdthe bone fragments in alignmentr during the process of knitting or healing. In order to introduce the ordinary medullary pin now in use, into a bone such as a femur, for example, the surgeon must first make an incision over the hip joint and drill through the cortex of the bone medial to the trochanter major. The pin is then introduced from the outside into the upper` fragmentof the bone, and

thereafter the lower fragment must be ,aligned with the upper in order to introduce or manipulate the pin into the lower fragment.

However, when there is much over-riding or greatA displacement of the bone fragments, it is necessary, besides introducing the 'pinA through the first operative area over the hip, to resortto open reduction over thefractured area in order to bring `the two ends into apposition. Also, in old fractures where there are adhesions orinterposed tissues'between the fragments, it is necesopen reduction in one operative area only, thus having considerable advantage over prior medullary pins and prior'methods of reducingfbone fractures. y Y i g Y .Y

When the usual one-piece pin was employed, it was the custom to leave one end of thepin in a projecting position so that when sunicient knitting of the bone fragments had taken place the pin could be removed; According to the present invention, however, thepin is preferably made of non-magnetic surgical stainless- `'steel and remains permanently within the-"medullary cavityof the bone.V y n ne objectof'the'present invention is to provide a new and improved self-retaining medullary extension pin for use in securing fractured bones in alignment during the knitting period, Without having to be anchored or secured with wires or other suture material to the voutside of the bone.

A still further object of the invention is to provide a self-retaining intramedullary pin or splint for fractured bones which may be inserted in one of the bone fragments at the fractured area and provided with a telescoping part which may be projected or extended into the other fragment to hold the bone fragments in alignment.

A still further object of the invention is to provide a new method of reducing a fractured bone which comprises inserting into one of the bone fragments at the fractured area a splint structure comprising a sleeve having an outwardly spring-pressed pin therein, the pin being retained in a position substantially Wholly within the sleeve during the insertion, and then, after bringing the bone fragments into apposition, releasing the pin to permit it to be forced outwardly by the spring into the other bone fragment.

Still another object of the invention is to provide a self-retaining medullary extension pin comprising a sleeve having an outwardly spring-` pressed pin therein, the sleeve having an open end through which the pin may be projected by the spring, the pin having a relatively sharp point upon its extended end, and the sleeve being provided with an abutment for the spring adjacent the other end and being provided with an opening at said other end to permit circulation.

A still further object of the invention is to provide a self-retaining medullary pin of the character described in which means is provided for holding the pin in its retracted position substantially enclosed within the outer sleeve or shell in which it is telescopically mounted.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

Inthe accompanyingdrawings:

1 is a-'section'al'view of a fractured femur of a dog showing our self-retaining'medullary pin in its operative position.;

Fig. 2 is a view similar to Fig. l showing the bone fragments prior to the reductionI of the fracture but with the pin inserted into one of the fragments'through the end of thelooneiat.,the

fractured area;

Fig."3' iS View Y similar to Fig. 1""showing aA i fractured tibiaof `'a dog, the fracture lhaving been-' reduced by the use of our self-retaining medullary pin;

Fig. 4 is a similar view showing the bone fragments, there being considerable over-riding of the bone ends, and our splint structure having been inserted into one of the bone fragments through the end thereof at the point of fracture;

Fig. t5 is.a-.sectional view of .our self-retaining medullary ."extex'isionv pin Fig. 6 is a side elevational view of the splint showing the pin in retracted position; and

Fig. '7 is a rear end elevational View of the outer sleeve of the splint. v

To illustrate a preferred embodiment of thev invention, we have shown a self-retaining medullary extension pin or splint comprising an outer casing or sleeve I0, shown herein, of cylindrical for-m, but other shapes may" be employewif* desired. As shown, the member II! is hollow and preferably formed of seamless tubing.

Slidablyor.telescopically, disposed within the sleeve orcasinglll'is la pin II, thisV pin being of.

the same shape in cross section as th'esleeve and. ttingsnugly therein. The outer end'ofthe pin is .preferablyprovidedV with a relatively. sharp, but somewhat rounded, end I2,v` this point being. formedbyprovidingithe flatfaces I3, there being' threeof suchfaces ,asv illustrated, .thus making the endof .thepinofsomewhat roundedl pyramidalfcrm. The function oflthe sharpened end of thepin willbe explained hereinafter.

Atfits inner end .the pin is .preferably provided witha blunt endoriiat' surface Magainst which a compression spring I5 reacts, this spring being. positioned .within` .the sleeve and. bearing. at its other` end against abutment means Iformed in the sleeve. y

This abutmentmeangmaybe.formed by displacinginwardly the -rnetalof` .the sleeve, as shown at .I'I, which may bedoneat a number .of points about the periphery ofthe sleeve, there-being fourA of `suehdisplacements, asi-shown in Fig. .7, thus forming longitudinal` corrugations. I8 .at .the rear end Vof thesleeve..L .There-Will, however, be an.

opening left .between-the inward displacedportions I'I so asl toprovide .forfreecirculation through the-sleeve, as When .thesplint -is inserted. into'the boneit will remain permanently .in place.. It may here be noted,`v` therefore, thatthe parts of the devieew-ill bemade of `non-magnetic surgical 'stainless-steel.' v

In order that` the l-pin IIv` may. be heldI in retracted position.V inwhich .itis substantially. enclosed' Within' the slee-veffID, the` walll ofthe latter is provided with. ai longitudinal. slotor`l groove I 9 -closed atvits .'outer. endratmZU- and :provided-with. .a :transverse -portionli at its inner.` end, theI latter :portioncommunicating with Y the longitudinal .portion I9. A-smallfretaining pin 22 is secured to the Apinfl I, the pin 22m-ding in the groove 2 I Itr will .be obvious with. this construction that when the vpin :22 `is within the :portion I9 of the slot in the-sleeve, .the spring,.-l5.will1 urgefthespinv II outwardly to itsfextendedaor-.protractedtposition,pas shownfin. Figr. Howeventhapin I I lmay be forced inwardlyagainst thetension` of the.. spring I5, and when the'retainingpinZZ reaches.- theiportion 2l ofthefslot in thesleeve, the pin I I may be given a slight turn, thus 'bringing theretainingpin22 in .the Vtransverse portion2l of the? slot isonthat; Athe .pin :I I Wil1:.be--iretained-r.in its retracted position, shown in Figa..6. f InLvthis-'Il positionsonlyv afs'mall portion `oith'e pointjprcjects. fronrrfthesleevepand..thisspoint mam-.ber

grasped with a small instrument and the pin II rotated to bring the retaining pin in alignment with the slot portion I9 so as to permit the projection of the pin I I.

It may also be noted that, if desired, the slot portions I9 and 2l may be omitted. In this case when the device is being inserted the pin I2 may bra-.held in its retractedi..position,. shown inFig. 6, by a thinbladedf instrument lor the like, and after the bone fragments are aligned, the pin IIfmay .be released by this instrument so that it may be projected outwardly by its spring to its In Figs. 1 and 2 of the drawings we have shown the femur .cfa dog, for example, showing the use and application of our improved medullary pin. The cortex ofthe bone is shown at 23, the medullary'cavityat"`24-,' and the marrow at 25. In this-instance, as illustrated, there is a considerable separation of the bone frag-ments. In treatingaifracture ofthis kind,.the pin .I l isretracted into the` sleeveJll, as .shown in. Fig. 6, andthe. device inserted into the bone fragment. 26,. as. shown at'the lowerportion of Fig.- 2.. Thereafter. the upper-fragment .ZI'isbrough't into apposition with the lower fragment so that the .two partscf.

the bones. are aligned.. When .this is done the pointed .end offthevpin-MII may be engaged by a'. small instrument and. given a slight rotation, thus` releasing theretaining pinv 22.!fromthe transverse portion 2| of the slot .inthensleeve Thispermitsthe spring. I5 to drive the pin-.II intotheupper. fragment 21. ofthe bonefor its full distance;`

Thus `the entire pin splint isseated. rmly inboth of the-.bone fragments` so thatthere 'will` be no movement of the. pin, and the vfragments will be.

held firmly inalignedaposition.

It will, of course-,Ibeunderstood 4thatboth .the

sleeve IIland pin II-maybe of various sizes and lengths depending upon the length andthetype of the fractured bone,.- and the spring will alsov be of the proper-length and tension for the parf ticular application-to which it is -to beput.

In Figs. 3 and 4-ofthe drawing wehavefshown be `inserted into one `of thefbone ffragments,y suchv asthe fragment` 28, with the Pin. Il infitsf retracted position,l andfthereafterwhenthe bonef fragments have' been aligned;` therpin-I I vwill. .be

releasedfandfwill be-drivenrmly intothe med.- ullary'y cavity of..1.the-fotlierbone .fragment 28; so

as' -tovseat -.-the pinfstructure: rmlyuin place and.

hold thebones-in alignment.n

n wm. 10e-.seen that .with-this. technique only. one i operative..area. is required, Vnamely `that at the fractured area.- lvioreover,l itY requires-eno.

drillingl through the I end .of lthe bone, i and, therefore', f not -only reduces: thetime. required.for4 the;` operationfpbut. also reduces-.ther.arealikely to. .ba`

infected.

While...v Wec .-have.- shown and -described .a preferrea, embodiment of- -our invention.. and apre-1 ferred` method/of .its use, i it :is-to nbe' understood` that the A.invention .is not limited to all ofthe.- detailsrshownv orto the .exact steps described, but is capable of modicationand .variation within; the g spirit-.of..the:-inventiorrand l within...the scope.'

01%tlieeppehdedblaifhS-- What We claim is: l .1.. .frmedullary.K splint. structure. for; use.; nireducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, and the outer end of said pin being provided with a relatively sharp point.

2. A medullary splintJ structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, the outer end of said pin being provided with a relatively sharp point, and cooperating means on said pin and sleeve to hold the pin in retracted position in the sleeve against the action of the spring with the pin substantially enclosed by the sleeve.

'3. A medullary splint structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, the outer end of said pin being provided with a relatively sharp point, cooperating means on said pin and sleeve to hold the pin in retracted position in the sleeve against the action of the spring with the pin substantially enclosed by the sleeve, said means comprising a longitudinal slot in the sleeve closed at its outer end and provided with a transverse portion at its inner end, and a projecting member on the pin slidably received in said slot.

4. A medullary splint structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, and the outer end of said pin being provided with a relatively sharp point, said sleeve having an abutment at its other end against which the spring reacts.

5. A medullary splint structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, the outer end of said pin being reduced in cross sectional size, and said sleeveA having an opening of reduced size at its other end to permit circulation through the sleeve.

6. A medullary splint structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the pin projects from the sleeve, and the outer end of said pin being provided with a relatively sharp point, and said sleeve having its wall displaced inwardly at spaced points adjacent its other end to provide abutment means for the spring and leave an opening through this end of the tube.

'7. A medullary splint structure for use in reducing a bone fracture comprising a sleeve open at one end, a pin slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin to force it outwardly through the open end of the sleeve to a projected position wherein a considerable portion of the p-in projects from the sleeve, the outer end of said pin being provided with a relatively sharp point, cooperating means on said pin and sleeve to hold the pin in retracted position in the sleeve against the action of the spring with the pin substantially enclosed by the sleeve, said means comprising a longitudinal slot in the sleeve closed at its outer end and provided with a transverse portion at its inner end, a projecting member on the pin slidably received in said slot, and the pointed end of said pin having flat sides thereon to facilitate rotation thereof to release the pin.

8. A medullary splint structure for use in reducing a bone fracture comprising a sleeve member open at one end, a pin member slidably received within said sleeve, a 4compression spring within the sleeve acting against the inner end oi the pin member to force it outwardly through the open end of the sleeve member to a projected position wherein a considerable portion of the pin member projects from the sleeve member, the outer end of said pin member being provided with a relatively sharp point, and cooperating means to hold the pin member in retracted position in the sleeve, said means comprising a pin in one of said members and a groove in the other of said members in which the pin is slidably received.

9. A medullary splint structure for use in reducing a bone fracture comprising a sleeve member open at one end, a pin member slidably received within said sleeve, a compression spring within the sleeve acting against the inner end of the pin member to force it outwardly through the open end of the sleeve member to a projected position wherein a considerable portion of the pin member projects from the sleeve member, cooperating means on said pin and sleeve to guide the pin in its movements and to limit the projection of the pin outwardly by the spring.

SALO JONAS. ALBERT M. JONAS.

References Cited in the le 0f this patent The International Journal of Surgery for February 1916, pages 33-35, vol. 29, No. 2. (Copy in Division 55.) 

